// universal hash functions
// P  key range
// M hash range
template<int a,int b>
int hash(int k){
	return (a*k+b)%P%M;
}

int ELFhash(char *key){
	unsigned long h;
	while(*key){
		h=(h<<4)+ *key ++;
		unsigned long g=h & 0xf0000000L;
		if(g) h^=g>>24;
		h&= ~g;
	}
	return h%M;
}

// RS Hash Function
unsigned int RSHash(char *str)
{
        unsigned int b = 378551;
        unsigned int a = 63689;
        unsigned int hash = 0;

        while (*str)
        {
                hash = hash * a + (*str++);
                a *= b;
        }

        return (hash & 0x7FFFFFFF);
}

// JS Hash Function
unsigned int JSHash(char *str)
{
        unsigned int hash = 1315423911;

        while (*str)
        {
                hash ^= ((hash << 5) + (*str++) + (hash >> 2));
        }
        
        return (hash & 0x7FFFFFFF);
}

// P. J. Weinberger Hash Function
unsigned int PJWHash(char *str)
{
        unsigned int BitsInUnignedInt = (unsigned int)(sizeof(unsigned int) * 
8);
        unsigned int ThreeQuarters    = (unsigned int)((BitsInUnignedInt  * 3)
 / 4);
        unsigned int OneEighth        = (unsigned int)(BitsInUnignedInt / 8);

        unsigned int HighBits         = (unsigned int)(0xFFFFFFFF) << (BitsInU
nignedInt - OneEighth);
        unsigned int hash             = 0;
        unsigned int test             = 0;

        while (*str)
        {
                hash = (hash << OneEighth) + (*str++);
                if ((test = hash & HighBits) != 0)
                {
                        hash = ((hash ^ (test >> ThreeQuarters)) & (~HighBits)
);
                }
        }

        return (hash & 0x7FFFFFFF);
}

// ELF Hash Function
unsigned int ELFHash(char *str)
{
        unsigned int hash = 0;
        unsigned int x    = 0;

        while (*str)
        {
                hash = (hash << 4) + (*str++);
                if ((x = hash & 0xF0000000L) != 0)
                {
                        hash ^= (x >> 24);
                        hash &= ~x;
                }
        }

        return (hash & 0x7FFFFFFF);
}

// BKDR Hash Function
unsigned int BKDRHash(char *str)
{
        unsigned int seed = 131; // 31 131 1313 13131 131313 etc..
        unsigned int hash = 0;

        while (*str)
        {
                hash = hash * seed + (*str++);
        }

        return (hash & 0x7FFFFFFF);
}

// SDBM Hash Function
unsigned int SDBMHash(char *str)
{
        unsigned int hash = 0;

        while (*str)
        {
                hash = (*str++) + (hash << 6) + (hash << 16) - hash;
        }

        return (hash & 0x7FFFFFFF);
}

// DJB Hash Function
unsigned int DJBHash(char *str)
{
        unsigned int hash = 5381;

        while (*str)
        {
                hash += (hash << 5) + (*str++);
        }

        return (hash & 0x7FFFFFFF);
}

// AP Hash Function
unsigned int APHash(char *str)
{
        unsigned int hash = 0;
        int i;

        for (i=0; *str; i++)
        {
                if ((i & 1) == 0)
                {
                        hash ^= ((hash << 7) ^ (*str++) ^ (hash >> 3));
                }
                else
                {
                        hash ^= (~((hash << 11) ^ (*str++) ^ (hash >> 5)));
                }
        }

        return (hash & 0x7FFFFFFF);
}